Speedometer for vessels.



G. F. ROPER.

SPEEDOMETER FOR VESSELS. APPLIOATION FILED Nov. 21, 1910.

Patented Dec. 24, 1912.

UNITED sTATEs PATENT OFFICE.-

CHARLES F. ROPER, 0F HOPEDALE, MASSACHUSETTSYASSIGNOR TO C. F. KOPER! i COMPANY, '0F HOPEDALE, MASSACHUSETTS, A FIRM.

SPEEDOMETER FOR. VESSELS.

This invention has for its object the production of a simple and eiiicient speedometer adapted for useon power or other vessels to .indicate thespeed at which the vessel is moving.

By reason .of its simplicity and moderate 1 fiist lcost my invention is particularly adaptfonuse on the smaller motor-boats havvliiigx speeds of from say three to fifteen or 2o twenty miles per hour. i

.In accordance with, my invention the speedometer;coinprehends a water column 'the height of which'isV variable in an approgima-tely fixed ratiovto the speed of the yvesse'lf (substantially as the square of the speed); an indicator consisting of a column -of a suitable liquid, such as mercury, and

an adjacent .graduated scale, and a fluid transmittin medium connectingsaid water column an the indicating column, whereby variations in the height of the waterv column due to changes in the speed of the vessel will cause corresponding changes in the height of the indicating column.

These and other novel features of my in- 4 vention will be fully described in the subjoined specification and particularlypointed out in the vfollowing claims.

Figure 1 is a side elevation, partly brokenout, of a power boat provided with a speedometer embodying one practical form of my 4present invention; Fig. 2 is an enlarged front elevation of t-he speed indicating device and its support; Fig. 3 is a like view of the speed indicating device, but partly pipe for the water column; Fig. 7 is a lon-4 gitudinal sectional view, enlarged, of a cushionin or retarding device interposed between t e water and indicating columns;4

Specication of Letters Patent. Application ,filed November 21, 1910. Serial No. 593,305.

Fig. 8 is a lsimilar view of an equalizer which is arranged to control the transmittin cating columns, as will be described.

Patented Dec. 24, 1912.

medium between the water and indi- InA Fig. 1 a power boat A of any suitable character is herein provided with an upright metal tube or stand-pipe 1 having a rela# tively small diameter, and provided at its formed on the bottom ofthe plate 2 openI at its forward end, toward theV bow of the vessel, at 4, the rear"\wall a'nd bottom 5 of said'l chamber'preferably being curved to yfacilitate the passage of the water through the intake chamber and thence upward into the. foot ofthe standfpipe 1. A triangular blade or fin 6 depending 'from the plate 2 ahead of the chamber and equi-distant from its side walls serves to prevent the entrance of weeds or other obstructions into the chamber, the inclined lower edge 7, which leads from the plate downward to the `bottom 5 of said chamber, servin to shed such obstructions from the inlet 4 o the chamber, as will be manifest. I leave a clearance 8, Fig. 5, between the inletl.- and the after end of the fin, so that ifthe inlet at one side of said fin should be clogged the water rushing into the other side of the inlet 4,will also traverse the clearance 8 and throw out the obstruction to thereby clear the clogged side .ofthe inlet. This construction of the intake fof the stand-pipe is an important fealower end with an elongated fiat lplate 2 ture of my invention, for to secure the most efficient operation of the speedometer it.- is4 absolutely necessary that the watei shall at all times have free entrance tov the stand- 1 pipe; in order that the column of water therein may rise and fall in accordance with variations in the vessels speed. While the,

vessel is at rest the water 'in the standpipe lrises to-theheight of j-the water-level of the vessel, but when the vessel begins to move and thereby produces pressure upon the water column in.,l the stand-pipe said column rises at a ratio, which-is .approximately as the square of the speedfof the vessel. Changesl in the depth of immprsion of the vessel, bywloading :and unloading, will of course vary the height of the water column ,when thafvessel is at:rest,-butf as will be explained this variation is provided for so that it does not interfere with the speed indications.

The speed indicating device will now be described, having reference to Figs. 2, 3 and 4. A box-like casting 9, having bosses 10 through which are passed the Shanks of attaching screws 11, is secured in an upright position on any convenient part of the vessel, the face of the casting having extended therefrom an ear 12, Figs. 1 and 4. By means of a vertical pivot screw 13 the speed indicating device is connected with said ear, so that it can be swung upon such pivot into position for convenient inspection. An elongated and substantially rectangular plate 14, preferably of cast iron, and thickened at its lower end, has on its back an enlargement 15 which rests on the ear 12 and receives the pivot screw 13, supporting the plate in an inclined position, the face of the plate having formed in it a central longitudinal gutter or groove 16 communicating at its lower end by asmall hole 17, Fig. 4, with a liquid reservoirv18. The reservoir is conveniently made Vby drilling the thickened part of the plate 14, the lower end of the reservoir being tightlyclosed by a screw-plug 19 after the mercury M is introduced. A tubular nipple 20 communicates with the upper end of said reservoir and has securely attached to it one end of a rubber or other exible tube 21 connected atv its other end to the top of the stand-pipe l, see Fig. 1. Escape of the li uid through the nipple is prevented by a elt or similar plug 22, the latter, however, bein pervious to air, the pressure ltransmittlng medium between the water and indicating columns, mercury being probably the most satisfactory liquid for the indicating column. The groove 16 is flanked by flat-faced ribs 23, Fig. 3, continued around the upper and lower ends of said groove and upon the ribs is laid a sheet 24 of glass 'or transparent celluloid, preferably the latter because of its freedom from breakage, such sheet being pressed ti htly upon the ribs by a cover-plate 25, so t at said sheet and-the groove 16 form a closed tube having a transparent side and always communicating at its lower' end with the mercury reservoir. The cover-plate 25 has a central slot 26 which registers with the sides of the groove and forms a si ht opening, and one side of thev slot is gra uated to form a scale S, while correspondin ly placed numbers from zero up indicate t e speed in miles per hour,as

shown in Fig. 2. The scale is raduated in any suitable manner, the zero eing at the bottom and at such a point that when the vessel is at rest the level of the mercury in the reservoir and lower end of the communicating tube will Astand opposite the zero mark. A hole 27 at the upper end of groove 16 has a felt plug 28 therein, so that integra the air in the tube above the mercury column is always at atmospheric pressure, the plug preventing any accidental escape of the mercury. Screws 29 hold the cover-plate 25 in place, and in order that it shall always press tightly upon the transparent sheet or side 24 of the mercury tube the face of the plate 14 is recessed outside the ribs 23 to leave an edge rib 30 the face of which is in the plane of the faces of the ribs 23. The screws 29 pass into the recessed parts of the plate 14, so that when said screws are set up tightly any desired pressure4 of the coverplate upon the sheet 24 can be exerted, whereby no mercury can escape between said sheet and its supportingy ribs 23. Holes 31, 32, Fig. 4, in the front and bottom of the casting 9 permit the flexible tube 21 'to be passed therethrough, supporting the tube at the casting while at the same time ermitt-ing pivotal movement of the speed indicating member on the pivot 13.

From the foregoing description it will be apparent that when the vessel is at rest the mercury column 11 will stand at zero in the mercury tube of the speed indicating device, but when the vessel is in mot-ion the water column in the stand-pipe 1 will rise, and

through the transmitting body of alr con height of the water column. rlhe greater the speed of the vessel the higher will the water column rise in the stand-pipe, and the higher will thecolumn of mercury rise in its tube, said mercury and water columns falling as the speed diminishes, so that the speed attained by the vessel is indicated by that graduation of the scale S which is opposite the .top of the mercury column. v

lf the body of air between the water an mercury columns is perfectly free and unobstructed` the mercury will tend to jump rapidly by pitching or rolling motion of the boat, and to overcome this I interpose a cushion or retarding device in the transmit- 'ting medium. To this end the tube 21 is cut and between its severed ends l insert a metal sleeve 33 having a felt stopper 34 at each end, with sand 35 in the sleeve between the Stoppers, Fig. 7. rlhe Stoppers hold the granular material in the sleeve and permit the pressure' to be transmitted from the water column through the transmitting medium to the mercury, butin such manner that quick changes due to irregular movements of the vessel will be retarded or cushioned, so that while speed variations will be properly 'and promptly indicated by variations in the mercury column the latter will not jump up and down with every temporary change in the water column due to pitching or rolling motions of the vessel. As the transmitting medium in the tube 21 will expand or contract more or less by a rise or fall of the temperature of the out-- side air the speed indication might be incorrect on a hot day and correct on a cool day, or vice versa, and different loading of the boat might have an undesirable effect on the apparatus. To prevent this I provide an equalizing deyice, which is merely an air valve, the casing 36, Fig. 8, being inserted -in the transmitting tube 21, with a screw-valve 37. By unscrewing the valve olf its seat 38 the ltube 21 is brought into communication with theputside air and the pressure in said tube is thereby equalized, so that the mercury column will come to the zero point of the scale when the vessel is at rest. The air valve is then closed and the apparatus is ready for use, the equalization of the pressure having been effected.

The apparatus embodying my invention is 25.. very simple, it indicates the speed of a vessel very accurately and with promptness, and the indicating device can be set up at any convenient point to which the casting 9 can be attached. By swinging the scalecarrying iplate 14 on 1ts pivot 13 the scale and mercury column can be placed in the best position for inspection. Any surplus length of tubing 2,1 can be stowed away in the casting 9 by coiling it between or around the bosses 10, so that there is -no necessity for cutting the -tubing for a vessely wherein the distance between the standpipe and .indicating member maybe lessl than in another Vesse n,

Various changes or modifications in details of construction and arrangement may be made by those skilled in the art without departing from the spirit and scope of my invention as set forth in the claims annexed hereto.

Having fully described my invention, what I claim as new and desire to secure by. Letters Patent is:

1. In a speedometer for vessels, the combination with a ywater column variable in an approximately fixed ratioto the speed of the vessel and means to support the water A column, of. a mercury column land supportingl means therefor and an adjacent speed indicating scale, a tubular container for and to .confine Huid transmitting-medium, con` necting the top of the water column and the bottom of the mercury column, to cause variations in the height of the latter corresponding to changes in the water column due to variations in the speed of the vessel, and a cushioning device in said container for the fluid medium to prevent rapid fluctuation of the Amercury column due to irregular movements of the vessel, said cushioning device presenting a multiplicity of small,

irregular and non-continuous passages for the slow travel of the transmitting medium therethrough.

2. In a speedometer for vessels, the combination with a stand-pipe for,` admitting and confining a column of water varying in height with the speed of the vessel, a graduated mercury tube having a communicating mercury reservoir, an air-tube connecting the reservoir and the top of the standpipe, the body of air confined in said tube causing variations in the height of the mercury column Vcorresponding to variations in the height of i the water column due to changes in the speed of the vessel, and means slowly pervious to the passage of air, located in said air-tube to prevent lluctuation of the mercury column due' to irregular movements of the vessel, said means presenting a multiplicity of small, lirregular and non-continuous passages.A y

3./ In a speedometer for vessels, the combination wlth a stand-pipe for admitting and conning a column of waterva'rying in height with the speed of'the vessel, of a graduated mercury tube havin'ga communieating mercury reservoir, an'air-tube connecting the; reservoir and .the top of the stand-pipe, the bodyiofair ,confined insaid tube causing variations ,in the heightloithe mercury column corresponding to variations in the height .of-j thew'ater c'olmnd'ue to changes in lthe speed ofthe vessel, means in the air-tube to prevent fluctuations of ,the

mercury column due to irregular movementsv in an approximately xed ratio to the speed of the vessel, an intake chamber communieating with the water below the Water-line of the vessel, said chamber having an inlet in its end toward the bow lof the vessel, and

means in front of and spaced from the inletk end of the chamber 'to maintain the inlet clear of weeds` or other obstructions suspended in the water, said means being equildistant from the sides of the intake cham- 5In a speedometer for vessels, a standpipe having an elongated plate at its lower end, an intake chamber depending from said plate and open at one end, a longitudinal fin depending from the plate in front of the open end o the cham er and spaced therefrom but' in the central plane of the chamber, the lower edge of the fin inclining downward from thc plate to the bottom of the intake chamber adjacent its open end, said late, chamber and fin bein located outsi e the hulll of a yvessel below t e waterline thereof with the open end of the chamfore and aft clearing fin adjacent the inlet ber toward the bow of the Vessel, to admit a end of the intake chamber, to keep the inlet column of water into the stand-pipe, the thereof clear of weeds and other obstruc- 1b height of the column Varying with the tions. 5 speed ofthe vessel. l In testimony whereof, l have signed my 6. In aspeedometer for vessels, va standname to this specication, in the presence pipe to admit a column of water Varying in of two subscribing witnesses.

height according to the speed of the vessel an intake-chamber communicating with the7 CHARLES F' ROPER' .10 lower end of the stand-pipe outside the ves- Witnesses:

sel below the Water-line thereof, said cham- WILLIAM O. PERKINS,

ber having an inlet at its forward end, and a CLARE H. DRAPER. 

